1. Field of the Invention
The present invention relates to a method for producing an integrated optical device.
2. Description of the Related Art
Patent Reference 1 (Japanese Unexamined Patent Application Publication No. 2002-243964) describes the following method for producing an integrated optical device having a butt-joint structure. A first optical waveguiding layer including a first lower optical guiding layer, an active layer, and a first upper optical guiding layer, and a first upper cladding layer are sequentially grown on an InP substrate. Portions of the first upper cladding layer, the first upper optical guiding layer, and the active layer are removed by dry etching through an etching mask formed on the first upper cladding layer. The first optical waveguiding layer is then etched by a wet etching technique through the etching mask. At this time, a side surface of the first optical waveguiding layer undergoes side etching. On the InP substrate having been exposed by the wet etching, a second optical waveguiding layer and a second upper cladding layer are sequentially grown. Thus, the butt-joint coupling between the first optical waveguiding layer and the second optical waveguiding layer is achieved.